Every spring I get larger black ants coming into my house mostly in the kitchen. I also see them outside the house and climbing around the base structure. I have determined that they are not termites. I tried using a bate last year but unlike all of the smaller colonies of ants that I gave the bate to (which I haven't seen in the house only in the driveway and sidewalks) which immediately started loading it up to take back to the nest, these ants weren't interested. Is there a reason? What kind of ant might they be and therefore what kind of bate do I need to use?



If they are larger ants that don't respond well to baits,  they are likely carpenter ants. Carpenter ants have a more diverse feeding habit than do some other common pest ants.  They will eat protein, sugary things, and also vegetative material.  Baits are formulated with specific eating habits in mind, and in some cases for a particular type of ant.  Some of the carpenter ants may have picked up bait, but since they have such diverse eating habits they did not all swarm to it and take it back to the nest.

We might try using a gel and a granular bait that is geared more specifically toward carpenter ants. To really treat carpenter ants, though, you have to treat possible moisture issues in your house that keep them around.

In the meantime, I just finished a fact sheet on carpenter ants. You can access this fact sheet by copying and pasting this URL, http://extension.usu.edu/files/publications/factsheet/carpenter-ant08.pdf

Posted on 4 Jun 2008

Ryan Davis
Arthropod Diagnostician, Utah Plant Pest Diagnostic Laboratory

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